John Sims (13 October 1749 – 26 February 1831) was an English physician and botanist. He was born in Canterbury, Kent and was subsequently educated at the Quaker school in Burford, Oxfordshire, he then went on to study medicine at Edinburgh University. Later in life he moved to London (1766) where he worked as a physician. Notably, he was called in to assist with Princess Charlotte's labor, but mother and baby both died. He was the first editor of Curtis's Botanical Magazine.